1 /* 2 * Block driver for the QCOW format 3 * 4 * Copyright (c) 2004-2006 Fabrice Bellard 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 25 #include "qemu/osdep.h" 26 #include "qapi/error.h" 27 #include "qemu/error-report.h" 28 #include "block/block_int.h" 29 #include "block/qdict.h" 30 #include "sysemu/block-backend.h" 31 #include "qemu/module.h" 32 #include "qemu/option.h" 33 #include "qemu/bswap.h" 34 #include <zlib.h> 35 #include "qapi/qmp/qdict.h" 36 #include "qapi/qmp/qstring.h" 37 #include "qapi/qobject-input-visitor.h" 38 #include "qapi/qapi-visit-block-core.h" 39 #include "crypto/block.h" 40 #include "migration/blocker.h" 41 #include "crypto.h" 42 43 /**************************************************************/ 44 /* QEMU COW block driver with compression and encryption support */ 45 46 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 47 #define QCOW_VERSION 1 48 49 #define QCOW_CRYPT_NONE 0 50 #define QCOW_CRYPT_AES 1 51 52 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 53 54 typedef struct QCowHeader { 55 uint32_t magic; 56 uint32_t version; 57 uint64_t backing_file_offset; 58 uint32_t backing_file_size; 59 uint32_t mtime; 60 uint64_t size; /* in bytes */ 61 uint8_t cluster_bits; 62 uint8_t l2_bits; 63 uint16_t padding; 64 uint32_t crypt_method; 65 uint64_t l1_table_offset; 66 } QEMU_PACKED QCowHeader; 67 68 #define L2_CACHE_SIZE 16 69 70 typedef struct BDRVQcowState { 71 int cluster_bits; 72 int cluster_size; 73 int l2_bits; 74 int l2_size; 75 unsigned int l1_size; 76 uint64_t cluster_offset_mask; 77 uint64_t l1_table_offset; 78 uint64_t *l1_table; 79 uint64_t *l2_cache; 80 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 81 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 82 uint8_t *cluster_cache; 83 uint8_t *cluster_data; 84 uint64_t cluster_cache_offset; 85 QCryptoBlock *crypto; /* Disk encryption format driver */ 86 uint32_t crypt_method_header; 87 CoMutex lock; 88 Error *migration_blocker; 89 } BDRVQcowState; 90 91 static QemuOptsList qcow_create_opts; 92 93 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 94 95 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 96 { 97 const QCowHeader *cow_header = (const void *)buf; 98 99 if (buf_size >= sizeof(QCowHeader) && 100 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 101 be32_to_cpu(cow_header->version) == QCOW_VERSION) 102 return 100; 103 else 104 return 0; 105 } 106 107 static QemuOptsList qcow_runtime_opts = { 108 .name = "qcow", 109 .head = QTAILQ_HEAD_INITIALIZER(qcow_runtime_opts.head), 110 .desc = { 111 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 112 { /* end of list */ } 113 }, 114 }; 115 116 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 117 Error **errp) 118 { 119 BDRVQcowState *s = bs->opaque; 120 unsigned int len, i, shift; 121 int ret; 122 QCowHeader header; 123 Error *local_err = NULL; 124 QCryptoBlockOpenOptions *crypto_opts = NULL; 125 unsigned int cflags = 0; 126 QDict *encryptopts = NULL; 127 const char *encryptfmt; 128 129 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 130 encryptfmt = qdict_get_try_str(encryptopts, "format"); 131 132 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 133 false, errp); 134 if (!bs->file) { 135 ret = -EINVAL; 136 goto fail; 137 } 138 139 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 140 if (ret < 0) { 141 goto fail; 142 } 143 be32_to_cpus(&header.magic); 144 be32_to_cpus(&header.version); 145 be64_to_cpus(&header.backing_file_offset); 146 be32_to_cpus(&header.backing_file_size); 147 be32_to_cpus(&header.mtime); 148 be64_to_cpus(&header.size); 149 be32_to_cpus(&header.crypt_method); 150 be64_to_cpus(&header.l1_table_offset); 151 152 if (header.magic != QCOW_MAGIC) { 153 error_setg(errp, "Image not in qcow format"); 154 ret = -EINVAL; 155 goto fail; 156 } 157 if (header.version != QCOW_VERSION) { 158 error_setg(errp, "Unsupported qcow version %" PRIu32, header.version); 159 ret = -ENOTSUP; 160 goto fail; 161 } 162 163 if (header.size <= 1) { 164 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 165 ret = -EINVAL; 166 goto fail; 167 } 168 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 169 error_setg(errp, "Cluster size must be between 512 and 64k"); 170 ret = -EINVAL; 171 goto fail; 172 } 173 174 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 175 * so bytes = num_entries << 3. */ 176 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 177 error_setg(errp, "L2 table size must be between 512 and 64k"); 178 ret = -EINVAL; 179 goto fail; 180 } 181 182 s->crypt_method_header = header.crypt_method; 183 if (s->crypt_method_header) { 184 if (bdrv_uses_whitelist() && 185 s->crypt_method_header == QCOW_CRYPT_AES) { 186 error_setg(errp, 187 "Use of AES-CBC encrypted qcow images is no longer " 188 "supported in system emulators"); 189 error_append_hint(errp, 190 "You can use 'qemu-img convert' to convert your " 191 "image to an alternative supported format, such " 192 "as unencrypted qcow, or raw with the LUKS " 193 "format instead.\n"); 194 ret = -ENOSYS; 195 goto fail; 196 } 197 if (s->crypt_method_header == QCOW_CRYPT_AES) { 198 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 199 error_setg(errp, 200 "Header reported 'aes' encryption format but " 201 "options specify '%s'", encryptfmt); 202 ret = -EINVAL; 203 goto fail; 204 } 205 qdict_put_str(encryptopts, "format", "qcow"); 206 crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 207 if (!crypto_opts) { 208 ret = -EINVAL; 209 goto fail; 210 } 211 212 if (flags & BDRV_O_NO_IO) { 213 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 214 } 215 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.", 216 NULL, NULL, cflags, errp); 217 if (!s->crypto) { 218 ret = -EINVAL; 219 goto fail; 220 } 221 } else { 222 error_setg(errp, "invalid encryption method in qcow header"); 223 ret = -EINVAL; 224 goto fail; 225 } 226 bs->encrypted = true; 227 } else { 228 if (encryptfmt) { 229 error_setg(errp, "No encryption in image header, but options " 230 "specified format '%s'", encryptfmt); 231 ret = -EINVAL; 232 goto fail; 233 } 234 } 235 s->cluster_bits = header.cluster_bits; 236 s->cluster_size = 1 << s->cluster_bits; 237 s->l2_bits = header.l2_bits; 238 s->l2_size = 1 << s->l2_bits; 239 bs->total_sectors = header.size / 512; 240 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 241 242 /* read the level 1 table */ 243 shift = s->cluster_bits + s->l2_bits; 244 if (header.size > UINT64_MAX - (1LL << shift)) { 245 error_setg(errp, "Image too large"); 246 ret = -EINVAL; 247 goto fail; 248 } else { 249 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 250 if (l1_size > INT_MAX / sizeof(uint64_t)) { 251 error_setg(errp, "Image too large"); 252 ret = -EINVAL; 253 goto fail; 254 } 255 s->l1_size = l1_size; 256 } 257 258 s->l1_table_offset = header.l1_table_offset; 259 s->l1_table = g_try_new(uint64_t, s->l1_size); 260 if (s->l1_table == NULL) { 261 error_setg(errp, "Could not allocate memory for L1 table"); 262 ret = -ENOMEM; 263 goto fail; 264 } 265 266 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 267 s->l1_size * sizeof(uint64_t)); 268 if (ret < 0) { 269 goto fail; 270 } 271 272 for(i = 0;i < s->l1_size; i++) { 273 be64_to_cpus(&s->l1_table[i]); 274 } 275 276 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 277 s->l2_cache = 278 qemu_try_blockalign(bs->file->bs, 279 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 280 if (s->l2_cache == NULL) { 281 error_setg(errp, "Could not allocate L2 table cache"); 282 ret = -ENOMEM; 283 goto fail; 284 } 285 s->cluster_cache = g_malloc(s->cluster_size); 286 s->cluster_data = g_malloc(s->cluster_size); 287 s->cluster_cache_offset = -1; 288 289 /* read the backing file name */ 290 if (header.backing_file_offset != 0) { 291 len = header.backing_file_size; 292 if (len > 1023 || len >= sizeof(bs->backing_file)) { 293 error_setg(errp, "Backing file name too long"); 294 ret = -EINVAL; 295 goto fail; 296 } 297 ret = bdrv_pread(bs->file, header.backing_file_offset, 298 bs->backing_file, len); 299 if (ret < 0) { 300 goto fail; 301 } 302 bs->backing_file[len] = '\0'; 303 } 304 305 /* Disable migration when qcow images are used */ 306 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 307 "does not support live migration", 308 bdrv_get_device_or_node_name(bs)); 309 ret = migrate_add_blocker(s->migration_blocker, &local_err); 310 if (local_err) { 311 error_propagate(errp, local_err); 312 error_free(s->migration_blocker); 313 goto fail; 314 } 315 316 qobject_unref(encryptopts); 317 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 318 qemu_co_mutex_init(&s->lock); 319 return 0; 320 321 fail: 322 g_free(s->l1_table); 323 qemu_vfree(s->l2_cache); 324 g_free(s->cluster_cache); 325 g_free(s->cluster_data); 326 qcrypto_block_free(s->crypto); 327 qobject_unref(encryptopts); 328 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 329 return ret; 330 } 331 332 333 /* We have nothing to do for QCOW reopen, stubs just return 334 * success */ 335 static int qcow_reopen_prepare(BDRVReopenState *state, 336 BlockReopenQueue *queue, Error **errp) 337 { 338 return 0; 339 } 340 341 342 /* 'allocate' is: 343 * 344 * 0 to not allocate. 345 * 346 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start' 347 * to 'n_end' within the cluster) 348 * 349 * 2 to allocate a compressed cluster of size 350 * 'compressed_size'. 'compressed_size' must be > 0 and < 351 * cluster_size 352 * 353 * return 0 if not allocated, 1 if *result is assigned, and negative 354 * errno on failure. 355 */ 356 static int get_cluster_offset(BlockDriverState *bs, 357 uint64_t offset, int allocate, 358 int compressed_size, 359 int n_start, int n_end, uint64_t *result) 360 { 361 BDRVQcowState *s = bs->opaque; 362 int min_index, i, j, l1_index, l2_index, ret; 363 int64_t l2_offset; 364 uint64_t *l2_table, cluster_offset, tmp; 365 uint32_t min_count; 366 int new_l2_table; 367 368 *result = 0; 369 l1_index = offset >> (s->l2_bits + s->cluster_bits); 370 l2_offset = s->l1_table[l1_index]; 371 new_l2_table = 0; 372 if (!l2_offset) { 373 if (!allocate) 374 return 0; 375 /* allocate a new l2 entry */ 376 l2_offset = bdrv_getlength(bs->file->bs); 377 if (l2_offset < 0) { 378 return l2_offset; 379 } 380 /* round to cluster size */ 381 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size); 382 /* update the L1 entry */ 383 s->l1_table[l1_index] = l2_offset; 384 tmp = cpu_to_be64(l2_offset); 385 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 386 ret = bdrv_pwrite_sync(bs->file, 387 s->l1_table_offset + l1_index * sizeof(tmp), 388 &tmp, sizeof(tmp)); 389 if (ret < 0) { 390 return ret; 391 } 392 new_l2_table = 1; 393 } 394 for(i = 0; i < L2_CACHE_SIZE; i++) { 395 if (l2_offset == s->l2_cache_offsets[i]) { 396 /* increment the hit count */ 397 if (++s->l2_cache_counts[i] == 0xffffffff) { 398 for(j = 0; j < L2_CACHE_SIZE; j++) { 399 s->l2_cache_counts[j] >>= 1; 400 } 401 } 402 l2_table = s->l2_cache + (i << s->l2_bits); 403 goto found; 404 } 405 } 406 /* not found: load a new entry in the least used one */ 407 min_index = 0; 408 min_count = 0xffffffff; 409 for(i = 0; i < L2_CACHE_SIZE; i++) { 410 if (s->l2_cache_counts[i] < min_count) { 411 min_count = s->l2_cache_counts[i]; 412 min_index = i; 413 } 414 } 415 l2_table = s->l2_cache + (min_index << s->l2_bits); 416 BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); 417 if (new_l2_table) { 418 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 419 ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 420 s->l2_size * sizeof(uint64_t)); 421 if (ret < 0) { 422 return ret; 423 } 424 } else { 425 ret = bdrv_pread(bs->file, l2_offset, l2_table, 426 s->l2_size * sizeof(uint64_t)); 427 if (ret < 0) { 428 return ret; 429 } 430 } 431 s->l2_cache_offsets[min_index] = l2_offset; 432 s->l2_cache_counts[min_index] = 1; 433 found: 434 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 435 cluster_offset = be64_to_cpu(l2_table[l2_index]); 436 if (!cluster_offset || 437 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 438 if (!allocate) 439 return 0; 440 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); 441 assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE)); 442 /* allocate a new cluster */ 443 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 444 (n_end - n_start) < s->cluster_size) { 445 /* if the cluster is already compressed, we must 446 decompress it in the case it is not completely 447 overwritten */ 448 if (decompress_cluster(bs, cluster_offset) < 0) { 449 return -EIO; 450 } 451 cluster_offset = bdrv_getlength(bs->file->bs); 452 if ((int64_t) cluster_offset < 0) { 453 return cluster_offset; 454 } 455 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 456 /* write the cluster content */ 457 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 458 ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, 459 s->cluster_size); 460 if (ret < 0) { 461 return ret; 462 } 463 } else { 464 cluster_offset = bdrv_getlength(bs->file->bs); 465 if ((int64_t) cluster_offset < 0) { 466 return cluster_offset; 467 } 468 if (allocate == 1) { 469 /* round to cluster size */ 470 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 471 if (cluster_offset + s->cluster_size > INT64_MAX) { 472 return -E2BIG; 473 } 474 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size, 475 PREALLOC_MODE_OFF, NULL); 476 if (ret < 0) { 477 return ret; 478 } 479 /* if encrypted, we must initialize the cluster 480 content which won't be written */ 481 if (bs->encrypted && 482 (n_end - n_start) < s->cluster_size) { 483 uint64_t start_offset; 484 assert(s->crypto); 485 start_offset = offset & ~(s->cluster_size - 1); 486 for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) { 487 if (i < n_start || i >= n_end) { 488 memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE); 489 if (qcrypto_block_encrypt(s->crypto, 490 start_offset + i, 491 s->cluster_data, 492 BDRV_SECTOR_SIZE, 493 NULL) < 0) { 494 return -EIO; 495 } 496 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 497 ret = bdrv_pwrite(bs->file, 498 cluster_offset + i, 499 s->cluster_data, 500 BDRV_SECTOR_SIZE); 501 if (ret < 0) { 502 return ret; 503 } 504 } 505 } 506 } 507 } else if (allocate == 2) { 508 cluster_offset |= QCOW_OFLAG_COMPRESSED | 509 (uint64_t)compressed_size << (63 - s->cluster_bits); 510 } 511 } 512 /* update L2 table */ 513 tmp = cpu_to_be64(cluster_offset); 514 l2_table[l2_index] = tmp; 515 if (allocate == 2) { 516 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); 517 } else { 518 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); 519 } 520 ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 521 &tmp, sizeof(tmp)); 522 if (ret < 0) { 523 return ret; 524 } 525 } 526 *result = cluster_offset; 527 return 1; 528 } 529 530 static int coroutine_fn qcow_co_block_status(BlockDriverState *bs, 531 bool want_zero, 532 int64_t offset, int64_t bytes, 533 int64_t *pnum, int64_t *map, 534 BlockDriverState **file) 535 { 536 BDRVQcowState *s = bs->opaque; 537 int index_in_cluster, ret; 538 int64_t n; 539 uint64_t cluster_offset; 540 541 qemu_co_mutex_lock(&s->lock); 542 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 543 qemu_co_mutex_unlock(&s->lock); 544 if (ret < 0) { 545 return ret; 546 } 547 index_in_cluster = offset & (s->cluster_size - 1); 548 n = s->cluster_size - index_in_cluster; 549 if (n > bytes) { 550 n = bytes; 551 } 552 *pnum = n; 553 if (!cluster_offset) { 554 return 0; 555 } 556 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) { 557 return BDRV_BLOCK_DATA; 558 } 559 *map = cluster_offset | index_in_cluster; 560 *file = bs->file->bs; 561 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; 562 } 563 564 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 565 const uint8_t *buf, int buf_size) 566 { 567 z_stream strm1, *strm = &strm1; 568 int ret, out_len; 569 570 memset(strm, 0, sizeof(*strm)); 571 572 strm->next_in = (uint8_t *)buf; 573 strm->avail_in = buf_size; 574 strm->next_out = out_buf; 575 strm->avail_out = out_buf_size; 576 577 ret = inflateInit2(strm, -12); 578 if (ret != Z_OK) 579 return -1; 580 ret = inflate(strm, Z_FINISH); 581 out_len = strm->next_out - out_buf; 582 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 583 out_len != out_buf_size) { 584 inflateEnd(strm); 585 return -1; 586 } 587 inflateEnd(strm); 588 return 0; 589 } 590 591 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 592 { 593 BDRVQcowState *s = bs->opaque; 594 int ret, csize; 595 uint64_t coffset; 596 597 coffset = cluster_offset & s->cluster_offset_mask; 598 if (s->cluster_cache_offset != coffset) { 599 csize = cluster_offset >> (63 - s->cluster_bits); 600 csize &= (s->cluster_size - 1); 601 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 602 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 603 if (ret != csize) 604 return -1; 605 if (decompress_buffer(s->cluster_cache, s->cluster_size, 606 s->cluster_data, csize) < 0) { 607 return -1; 608 } 609 s->cluster_cache_offset = coffset; 610 } 611 return 0; 612 } 613 614 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp) 615 { 616 /* At least encrypted images require 512-byte alignment. Apply the 617 * limit universally, rather than just on encrypted images, as 618 * it's easier to let the block layer handle rounding than to 619 * audit this code further. */ 620 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 621 } 622 623 static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, uint64_t offset, 624 uint64_t bytes, QEMUIOVector *qiov, 625 int flags) 626 { 627 BDRVQcowState *s = bs->opaque; 628 int offset_in_cluster; 629 int ret = 0, n; 630 uint64_t cluster_offset; 631 struct iovec hd_iov; 632 QEMUIOVector hd_qiov; 633 uint8_t *buf; 634 void *orig_buf; 635 636 assert(!flags); 637 if (qiov->niov > 1) { 638 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 639 if (buf == NULL) { 640 return -ENOMEM; 641 } 642 } else { 643 orig_buf = NULL; 644 buf = (uint8_t *)qiov->iov->iov_base; 645 } 646 647 qemu_co_mutex_lock(&s->lock); 648 649 while (bytes != 0) { 650 /* prepare next request */ 651 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 652 if (ret < 0) { 653 break; 654 } 655 offset_in_cluster = offset & (s->cluster_size - 1); 656 n = s->cluster_size - offset_in_cluster; 657 if (n > bytes) { 658 n = bytes; 659 } 660 661 if (!cluster_offset) { 662 if (bs->backing) { 663 /* read from the base image */ 664 hd_iov.iov_base = (void *)buf; 665 hd_iov.iov_len = n; 666 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 667 qemu_co_mutex_unlock(&s->lock); 668 /* qcow2 emits this on bs->file instead of bs->backing */ 669 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 670 ret = bdrv_co_preadv(bs->backing, offset, n, &hd_qiov, 0); 671 qemu_co_mutex_lock(&s->lock); 672 if (ret < 0) { 673 break; 674 } 675 } else { 676 /* Note: in this case, no need to wait */ 677 memset(buf, 0, n); 678 } 679 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 680 /* add AIO support for compressed blocks ? */ 681 if (decompress_cluster(bs, cluster_offset) < 0) { 682 ret = -EIO; 683 break; 684 } 685 memcpy(buf, s->cluster_cache + offset_in_cluster, n); 686 } else { 687 if ((cluster_offset & 511) != 0) { 688 ret = -EIO; 689 break; 690 } 691 hd_iov.iov_base = (void *)buf; 692 hd_iov.iov_len = n; 693 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 694 qemu_co_mutex_unlock(&s->lock); 695 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 696 ret = bdrv_co_preadv(bs->file, cluster_offset + offset_in_cluster, 697 n, &hd_qiov, 0); 698 qemu_co_mutex_lock(&s->lock); 699 if (ret < 0) { 700 break; 701 } 702 if (bs->encrypted) { 703 assert(s->crypto); 704 if (qcrypto_block_decrypt(s->crypto, 705 offset, buf, n, NULL) < 0) { 706 ret = -EIO; 707 break; 708 } 709 } 710 } 711 ret = 0; 712 713 bytes -= n; 714 offset += n; 715 buf += n; 716 } 717 718 qemu_co_mutex_unlock(&s->lock); 719 720 if (qiov->niov > 1) { 721 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 722 qemu_vfree(orig_buf); 723 } 724 725 return ret; 726 } 727 728 static coroutine_fn int qcow_co_pwritev(BlockDriverState *bs, uint64_t offset, 729 uint64_t bytes, QEMUIOVector *qiov, 730 int flags) 731 { 732 BDRVQcowState *s = bs->opaque; 733 int offset_in_cluster; 734 uint64_t cluster_offset; 735 int ret = 0, n; 736 struct iovec hd_iov; 737 QEMUIOVector hd_qiov; 738 uint8_t *buf; 739 void *orig_buf; 740 741 assert(!flags); 742 s->cluster_cache_offset = -1; /* disable compressed cache */ 743 744 /* We must always copy the iov when encrypting, so we 745 * don't modify the original data buffer during encryption */ 746 if (bs->encrypted || qiov->niov > 1) { 747 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 748 if (buf == NULL) { 749 return -ENOMEM; 750 } 751 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 752 } else { 753 orig_buf = NULL; 754 buf = (uint8_t *)qiov->iov->iov_base; 755 } 756 757 qemu_co_mutex_lock(&s->lock); 758 759 while (bytes != 0) { 760 offset_in_cluster = offset & (s->cluster_size - 1); 761 n = s->cluster_size - offset_in_cluster; 762 if (n > bytes) { 763 n = bytes; 764 } 765 ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster, 766 offset_in_cluster + n, &cluster_offset); 767 if (ret < 0) { 768 break; 769 } 770 if (!cluster_offset || (cluster_offset & 511) != 0) { 771 ret = -EIO; 772 break; 773 } 774 if (bs->encrypted) { 775 assert(s->crypto); 776 if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) { 777 ret = -EIO; 778 break; 779 } 780 } 781 782 hd_iov.iov_base = (void *)buf; 783 hd_iov.iov_len = n; 784 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 785 qemu_co_mutex_unlock(&s->lock); 786 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 787 ret = bdrv_co_pwritev(bs->file, cluster_offset + offset_in_cluster, 788 n, &hd_qiov, 0); 789 qemu_co_mutex_lock(&s->lock); 790 if (ret < 0) { 791 break; 792 } 793 ret = 0; 794 795 bytes -= n; 796 offset += n; 797 buf += n; 798 } 799 qemu_co_mutex_unlock(&s->lock); 800 801 qemu_vfree(orig_buf); 802 803 return ret; 804 } 805 806 static void qcow_close(BlockDriverState *bs) 807 { 808 BDRVQcowState *s = bs->opaque; 809 810 qcrypto_block_free(s->crypto); 811 s->crypto = NULL; 812 g_free(s->l1_table); 813 qemu_vfree(s->l2_cache); 814 g_free(s->cluster_cache); 815 g_free(s->cluster_data); 816 817 migrate_del_blocker(s->migration_blocker); 818 error_free(s->migration_blocker); 819 } 820 821 static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts, 822 Error **errp) 823 { 824 BlockdevCreateOptionsQcow *qcow_opts; 825 int header_size, backing_filename_len, l1_size, shift, i; 826 QCowHeader header; 827 uint8_t *tmp; 828 int64_t total_size = 0; 829 int ret; 830 BlockDriverState *bs; 831 BlockBackend *qcow_blk; 832 QCryptoBlock *crypto = NULL; 833 834 assert(opts->driver == BLOCKDEV_DRIVER_QCOW); 835 qcow_opts = &opts->u.qcow; 836 837 /* Sanity checks */ 838 total_size = qcow_opts->size; 839 if (total_size == 0) { 840 error_setg(errp, "Image size is too small, cannot be zero length"); 841 return -EINVAL; 842 } 843 844 if (qcow_opts->has_encrypt && 845 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW) 846 { 847 error_setg(errp, "Unsupported encryption format"); 848 return -EINVAL; 849 } 850 851 /* Create BlockBackend to write to the image */ 852 bs = bdrv_open_blockdev_ref(qcow_opts->file, errp); 853 if (bs == NULL) { 854 return -EIO; 855 } 856 857 qcow_blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 858 ret = blk_insert_bs(qcow_blk, bs, errp); 859 if (ret < 0) { 860 goto exit; 861 } 862 blk_set_allow_write_beyond_eof(qcow_blk, true); 863 864 /* Create image format */ 865 ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp); 866 if (ret < 0) { 867 goto exit; 868 } 869 870 memset(&header, 0, sizeof(header)); 871 header.magic = cpu_to_be32(QCOW_MAGIC); 872 header.version = cpu_to_be32(QCOW_VERSION); 873 header.size = cpu_to_be64(total_size); 874 header_size = sizeof(header); 875 backing_filename_len = 0; 876 if (qcow_opts->has_backing_file) { 877 if (strcmp(qcow_opts->backing_file, "fat:")) { 878 header.backing_file_offset = cpu_to_be64(header_size); 879 backing_filename_len = strlen(qcow_opts->backing_file); 880 header.backing_file_size = cpu_to_be32(backing_filename_len); 881 header_size += backing_filename_len; 882 } else { 883 /* special backing file for vvfat */ 884 qcow_opts->has_backing_file = false; 885 } 886 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 887 unmodified sectors */ 888 header.l2_bits = 12; /* 32 KB L2 tables */ 889 } else { 890 header.cluster_bits = 12; /* 4 KB clusters */ 891 header.l2_bits = 9; /* 4 KB L2 tables */ 892 } 893 header_size = (header_size + 7) & ~7; 894 shift = header.cluster_bits + header.l2_bits; 895 l1_size = (total_size + (1LL << shift) - 1) >> shift; 896 897 header.l1_table_offset = cpu_to_be64(header_size); 898 899 if (qcow_opts->has_encrypt) { 900 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 901 902 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.", 903 NULL, NULL, NULL, errp); 904 if (!crypto) { 905 ret = -EINVAL; 906 goto exit; 907 } 908 } else { 909 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 910 } 911 912 /* write all the data */ 913 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0); 914 if (ret != sizeof(header)) { 915 goto exit; 916 } 917 918 if (qcow_opts->has_backing_file) { 919 ret = blk_pwrite(qcow_blk, sizeof(header), 920 qcow_opts->backing_file, backing_filename_len, 0); 921 if (ret != backing_filename_len) { 922 goto exit; 923 } 924 } 925 926 tmp = g_malloc0(BDRV_SECTOR_SIZE); 927 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 928 i++) { 929 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 930 tmp, BDRV_SECTOR_SIZE, 0); 931 if (ret != BDRV_SECTOR_SIZE) { 932 g_free(tmp); 933 goto exit; 934 } 935 } 936 937 g_free(tmp); 938 ret = 0; 939 exit: 940 blk_unref(qcow_blk); 941 qcrypto_block_free(crypto); 942 return ret; 943 } 944 945 static int coroutine_fn qcow_co_create_opts(const char *filename, 946 QemuOpts *opts, Error **errp) 947 { 948 BlockdevCreateOptions *create_options = NULL; 949 BlockDriverState *bs = NULL; 950 QDict *qdict; 951 Visitor *v; 952 const char *val; 953 Error *local_err = NULL; 954 int ret; 955 956 static const QDictRenames opt_renames[] = { 957 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 958 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 959 { NULL, NULL }, 960 }; 961 962 /* Parse options and convert legacy syntax */ 963 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true); 964 965 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 966 if (val && !strcmp(val, "on")) { 967 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 968 } else if (val && !strcmp(val, "off")) { 969 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 970 } 971 972 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 973 if (val && !strcmp(val, "aes")) { 974 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 975 } 976 977 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 978 ret = -EINVAL; 979 goto fail; 980 } 981 982 /* Create and open the file (protocol layer) */ 983 ret = bdrv_create_file(filename, opts, &local_err); 984 if (ret < 0) { 985 error_propagate(errp, local_err); 986 goto fail; 987 } 988 989 bs = bdrv_open(filename, NULL, NULL, 990 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 991 if (bs == NULL) { 992 ret = -EIO; 993 goto fail; 994 } 995 996 /* Now get the QAPI type BlockdevCreateOptions */ 997 qdict_put_str(qdict, "driver", "qcow"); 998 qdict_put_str(qdict, "file", bs->node_name); 999 1000 v = qobject_input_visitor_new_flat_confused(qdict, errp); 1001 if (!v) { 1002 ret = -EINVAL; 1003 goto fail; 1004 } 1005 1006 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 1007 visit_free(v); 1008 1009 if (local_err) { 1010 error_propagate(errp, local_err); 1011 ret = -EINVAL; 1012 goto fail; 1013 } 1014 1015 /* Silently round up size */ 1016 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW); 1017 create_options->u.qcow.size = 1018 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE); 1019 1020 /* Create the qcow image (format layer) */ 1021 ret = qcow_co_create(create_options, errp); 1022 if (ret < 0) { 1023 goto fail; 1024 } 1025 1026 ret = 0; 1027 fail: 1028 qobject_unref(qdict); 1029 bdrv_unref(bs); 1030 qapi_free_BlockdevCreateOptions(create_options); 1031 return ret; 1032 } 1033 1034 static int qcow_make_empty(BlockDriverState *bs) 1035 { 1036 BDRVQcowState *s = bs->opaque; 1037 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 1038 int ret; 1039 1040 memset(s->l1_table, 0, l1_length); 1041 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 1042 l1_length) < 0) 1043 return -1; 1044 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, 1045 PREALLOC_MODE_OFF, NULL); 1046 if (ret < 0) 1047 return ret; 1048 1049 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 1050 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 1051 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 1052 1053 return 0; 1054 } 1055 1056 /* XXX: put compressed sectors first, then all the cluster aligned 1057 tables to avoid losing bytes in alignment */ 1058 static coroutine_fn int 1059 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 1060 uint64_t bytes, QEMUIOVector *qiov) 1061 { 1062 BDRVQcowState *s = bs->opaque; 1063 QEMUIOVector hd_qiov; 1064 struct iovec iov; 1065 z_stream strm; 1066 int ret, out_len; 1067 uint8_t *buf, *out_buf; 1068 uint64_t cluster_offset; 1069 1070 buf = qemu_blockalign(bs, s->cluster_size); 1071 if (bytes != s->cluster_size) { 1072 if (bytes > s->cluster_size || 1073 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 1074 { 1075 qemu_vfree(buf); 1076 return -EINVAL; 1077 } 1078 /* Zero-pad last write if image size is not cluster aligned */ 1079 memset(buf + bytes, 0, s->cluster_size - bytes); 1080 } 1081 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 1082 1083 out_buf = g_malloc(s->cluster_size); 1084 1085 /* best compression, small window, no zlib header */ 1086 memset(&strm, 0, sizeof(strm)); 1087 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 1088 Z_DEFLATED, -12, 1089 9, Z_DEFAULT_STRATEGY); 1090 if (ret != 0) { 1091 ret = -EINVAL; 1092 goto fail; 1093 } 1094 1095 strm.avail_in = s->cluster_size; 1096 strm.next_in = (uint8_t *)buf; 1097 strm.avail_out = s->cluster_size; 1098 strm.next_out = out_buf; 1099 1100 ret = deflate(&strm, Z_FINISH); 1101 if (ret != Z_STREAM_END && ret != Z_OK) { 1102 deflateEnd(&strm); 1103 ret = -EINVAL; 1104 goto fail; 1105 } 1106 out_len = strm.next_out - out_buf; 1107 1108 deflateEnd(&strm); 1109 1110 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 1111 /* could not compress: write normal cluster */ 1112 ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0); 1113 if (ret < 0) { 1114 goto fail; 1115 } 1116 goto success; 1117 } 1118 qemu_co_mutex_lock(&s->lock); 1119 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset); 1120 qemu_co_mutex_unlock(&s->lock); 1121 if (ret < 0) { 1122 goto fail; 1123 } 1124 if (cluster_offset == 0) { 1125 ret = -EIO; 1126 goto fail; 1127 } 1128 cluster_offset &= s->cluster_offset_mask; 1129 1130 iov = (struct iovec) { 1131 .iov_base = out_buf, 1132 .iov_len = out_len, 1133 }; 1134 qemu_iovec_init_external(&hd_qiov, &iov, 1); 1135 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 1136 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 1137 if (ret < 0) { 1138 goto fail; 1139 } 1140 success: 1141 ret = 0; 1142 fail: 1143 qemu_vfree(buf); 1144 g_free(out_buf); 1145 return ret; 1146 } 1147 1148 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1149 { 1150 BDRVQcowState *s = bs->opaque; 1151 bdi->cluster_size = s->cluster_size; 1152 return 0; 1153 } 1154 1155 static QemuOptsList qcow_create_opts = { 1156 .name = "qcow-create-opts", 1157 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1158 .desc = { 1159 { 1160 .name = BLOCK_OPT_SIZE, 1161 .type = QEMU_OPT_SIZE, 1162 .help = "Virtual disk size" 1163 }, 1164 { 1165 .name = BLOCK_OPT_BACKING_FILE, 1166 .type = QEMU_OPT_STRING, 1167 .help = "File name of a base image" 1168 }, 1169 { 1170 .name = BLOCK_OPT_ENCRYPT, 1171 .type = QEMU_OPT_BOOL, 1172 .help = "Encrypt the image with format 'aes'. (Deprecated " 1173 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 1174 }, 1175 { 1176 .name = BLOCK_OPT_ENCRYPT_FORMAT, 1177 .type = QEMU_OPT_STRING, 1178 .help = "Encrypt the image, format choices: 'aes'", 1179 }, 1180 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 1181 { /* end of list */ } 1182 } 1183 }; 1184 1185 static BlockDriver bdrv_qcow = { 1186 .format_name = "qcow", 1187 .instance_size = sizeof(BDRVQcowState), 1188 .bdrv_probe = qcow_probe, 1189 .bdrv_open = qcow_open, 1190 .bdrv_close = qcow_close, 1191 .bdrv_child_perm = bdrv_format_default_perms, 1192 .bdrv_reopen_prepare = qcow_reopen_prepare, 1193 .bdrv_co_create = qcow_co_create, 1194 .bdrv_co_create_opts = qcow_co_create_opts, 1195 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1196 .supports_backing = true, 1197 .bdrv_refresh_limits = qcow_refresh_limits, 1198 1199 .bdrv_co_preadv = qcow_co_preadv, 1200 .bdrv_co_pwritev = qcow_co_pwritev, 1201 .bdrv_co_block_status = qcow_co_block_status, 1202 1203 .bdrv_make_empty = qcow_make_empty, 1204 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1205 .bdrv_get_info = qcow_get_info, 1206 1207 .create_opts = &qcow_create_opts, 1208 }; 1209 1210 static void bdrv_qcow_init(void) 1211 { 1212 bdrv_register(&bdrv_qcow); 1213 } 1214 1215 block_init(bdrv_qcow_init); 1216